   Parameters:
      ectx       _editable-context
      given      _current attribute name or column index
-     requested  _requested new attribute name")
-
-(defmethod change-object-name ::editable-context
+     requested  _requested new attribute name"
   [ectx given requested]
   (let [ obj-cols @(:obj-rows ectx) ]
     (if (= (type given) String)

(declare-multimethod change-object-name)
(declare-multimethod change-incidence-cross)

(inherit-multimethod change-incidence-cross ::editable-context
 "Sets or unsets the cross in the incidence relation of the editable-context.

  Parameters:
     ectx       _editable-context
     obj        _object
     att        _attribute
     cross      _true or false")

(defmethod change-incidence-cross ::editable-context
  [ectx obj att cross]
  (let [ ostr (if (= (type obj) String) obj
                (@(:obj-rows ectx) obj))

         fltr (rho filter (fn [x] (when-not (nil? x) x))) ]
    (set (fltr (map (*comp view names) sel)))))

(defn-typecheck get-selected-attributes ::context-editor-widget
  "Returns the set of selected attributes in the context-editor-widget.

  Parameters:
    widget  _context-editor-widget"
  [widget]
  (let [ table (get-table widget) 
         view (get-column-index-permutator table)
